To perform its mission, an aircraft comprises several pieces of equipment comprising parts flush with or appendages protruding from the skin of the aircraft.
These appendages or these flush parts for example belong to probes in particular making it possible to measure different aerodynamic parameters of the airflow surrounding the aircraft, in particular the total pressure, static pressure, temperature, or incidence of the airflow near the skin of the aircraft.
The total pressure, combined with the static pressure, makes it possible to determine the local speed of the airflow near the probe.
Other probes for example make it possible to measure the local incidence of an airflow.
The incidence probes may comprise moving appendages intended to be oriented in the axis of the airflow surrounding the probe.
The orientation of the probe makes it possible to determine the incidence of the airflow.
Other incidence probes may be equipped with stationary appendages equipped with several pressure taps.
The pressure difference measured between these pressure taps makes it possible to determine the incidence of the airflow surrounding the probe.
Other pieces of equipment such as cameras also must be installed flush or protruding relative to the skin of the aircraft, for example on pods.
During flight at high altitudes, the aircraft may encounter freezing conditions.
More specifically, ice may form on the skin and appendages of the aircraft. The appearance of ice is particularly problematic for the aerodynamic probes, the profiles of which may be modified by ice and the pressure tap orifices of which may be obstructed.
The measuring instruments mounted on pods may also be disrupted by the appearance of ice.
One solution making it possible to avoid ice formation consists of heating the appendages.
Currently, in most cases, heating is done using electrical resistances embedded in the appendages.
The heating is done by Joule effect. For example, to heat a total pressure probe, it is necessary to dissipate several hundred watts.
More specifically, this type of probe is formed by a mast bearing a tube closed at one of its ends and called Pitot tube.
The heating of the probe is done using a heating resistance made in the form of a heating wire wound around the body of the probe, i.e., both in the mast and the Pitot tube.
To produce the heating wire, an electrical conductor is commonly used including an alloy of iron and nickel coated with an insulating material such as alumina or manganese. The insulator itself is coated with a nickel or Inconel sheath allowing brazing of the wire on the body of the probe.
A method for producing such a probe is for example described in patent application FR 2,833,347 filed in the applicant's name.
The production of the heating wire and its assembly in the probe require a series of complex and costly operations.
Another embodiment to heat a Pitot tube probe had been considered in U.S. Pat. No. 4,275,603.
This document describes the use of a heat pipe contributing heat energy around the tube. The return of the heat transfer fluid to liquid state is ensured in a porous material.
This allows the probe to be arranged in any possible orientation on the skin of the aircraft.
In practice, this solution has no industrial advantage due to the difficulty of inserting a porous material in a probe.
The method for producing such a probe is at least as complex as that implementing a heating wire.